In recent years, with the development of mobile devices, further thinning of the semiconductor device has been desired. For this reason, it is required to reduce the thickness of the semiconductor chip to a range of 50 to 100 μm, or less. Generally, when backing-face grinding is carried out, a surface protective tape is laminated on a patterned face of the semiconductor wafer on which a circuit or the like is provided, whereby protection of the patterned face and fixation of the wafer are practiced, and then the backing-face grinding is carried out. After that, through various kinds of steps, such as dicing, picking-up, die-bonding, and resin sealing, a semiconductor device is produced.
When the semiconductor wafer is subjected to dicing, and is singulated into chips, singulation (dicing) of the wafer is carried out, by laminating a dicing tape on a backing face side (grinding side) of the semiconductor wafer, and thereby securing the wafer on the dicing tape. Accordingly, it is required that, when a wafer is subjected to dicing, the wafer is fixed with a sufficient adhesion force, and on the other hand, at the end of the dicing, the singulated chips are picked up from the dicing tape.
In dicing of the semiconductor wafer, cracks or cracking of the chips which are called chipping, occur, and the size thereof sometimes reaches 100 μm. In the advanced semiconductor device in terms of thinning thereof, even the chipping with several ten μm size, the chipping sometimes arrives at the patterned face, which results in reduction of the yield.
Such chipping is attributed to a fact that chips are vibrated by a rotary blade for cutting a wafer at the dicing, so that the chip and the rotary blade, or the chips are brought into contact with each other. In order to solve the problem of the chipping, Patent Literature 1 discloses a temporary-adhesive composition for more rigidly securing chips. However, a sufficient suppression of the chipping has not yet been achieved.
In recent years, various kinds of methods have been used in place of a dicing method using a rotary blade. In particular, plasma dicing has been perceived to be one of the most suitable steps of dividing into chips on the ground that vibration toward chips is not only suppressed, but also an etching speed is very high, and so on. Regarding the plasma dicing, for example, there is described in Patent Literature 2.